Placental protein and hormone measurements in twin pregnancy

Maternal serum levels of human placental lactogen (hPL), schwangerschaftsprotein 1 (SP1), pregnancy-associated plasma protein A (PAPP-A), placental protein 5 (PP5) and total oestriol (E3) were measured serially in 35 twin pregnancies during the third trimester. Eighteen pregnancies had major complications including dysmaturity of one or both fetuses in nine, premature labour in six, and placental abruption in three. Serum levels of all five variables were higher than in singletons, this distinction being greatest for hPL and lowest for SP1 and E3. The levels of hPL, PP5 and E3 just before delivery were significantly correlated with the total birthweight, a correlation with placental weight being evident only for hPL and PP5. A significant correlation between the five biochemical variables at 33-34 weeks was only seen between hPL and PAPP-A. Protein and hormone levels in the abnormal twin pregnancies were not apparently different from those in the normal twin pregnancies. These data suggest that only hPL levels biochemically reflect this extreme of fetal and placental growth, but that neither the levels of hPL nor any of the other biochemical indices examined are altered in abnormalities in twin pregnancy.     

Placental protein 10 (PP10) in singleton and twin pregnancy complicated by pre-eclampsia

Summary Circulating levels of placental protein 10 (PP10) were measured by radioimmunoassay in 140 women with normal singleton pregnancy (140 samples), in 6 women with normal twin pregnancy (15 samples) and in 35 pregnant women with pre-eclampsia (51 samples from singleton pregnancies and 7 samples from twin pregnancies) between 24 and 40 weeks. In singleton pregnancies with pre-eclampsia, the levels were lower than normal (P<0.01). In twin pregnancy the circulating PP10 levels were not significantly affected. These results suggest that changes in placental function are reflected in the circulating PP10 levels.     

Placental protein 5: Circulating levels in twin pregnancy and some observations on the analysis of biochemical data from multiple pregnancy

Blood was collected from 344 subjects with singleton pregnancy between 28 and 40 wk gestation, together with 70 samples from 24 subjects with twin pregnancy of comparable gestation. Circulating placental protein 5 (PP5) in singleton pregnancy rose from a median of 26 μg/l at 28 wk to reach a plateau with a median of 38 μg/l at 36 wk. The median PP5 levels in twin pregnancy were 50 μg/l at 28 wk rising to 65 μg/l at 38 wk.The ratio of the medians of PP5 levels in twin and singleton pregnancies fell from 1.94 at 28 wk to 1.62 at 38 wk. An ‘action line’ for low levels of PP5 in twin pregnancy was defined by applying a multiple of the median for twin pregnancy.     

Cord blood thyroid-stimulating hormone level in twin pregnancy

BACKGROUND: Cord blood thyroid-stimulating hormone level is elevated among neonates who undergo more perinatal stress. The aim of this study was to investigate the effect of twin pregnancy on the cord blood thyroid-stimulating hormone level. METHODS: The study group consisted of 24 910 singleton and 543 twin neonates over a 4-year period. The effect of twin pregnancy on the cord blood thyroid-stimulating level was evaluated. Linear regression analysis was used to control for the effect of mode of delivery, birth weight, and infant sex. RESULTS: The median cord blood thyroid-stimulating hormone levels (interquartile range) in the singletons and in the twins were 5.8mIU/l (4.2-8.6) and 5.6mIU/l (4.3-7.5), respectively. Linear regression analysis revealed no significant difference between singleton and twin cord blood thyroid-stimulating hormone levels (p = 0.23). Cord thyroid-stimulating hormone levels tended to be higher in second-born twins (p = 0.08) and monochorionic twins (p = 0.097) compared with singleton neonates. Twins with more than 20% weight discordance were associated with a significantly higher cord blood thyroid-stimulating hormone level (p = 0.035). CONCLUSION: Cord blood thyroid-stimulating hormone level is elevated in some subgroups of twins who are at higher risk of adverse perinatal outcomes. However, the overall effect of multiple pregnancy on the cord blood thyroid-stimulating hormone level is small. Cord blood thyroid-stimulating hormone screening for congenital hypothyroidism is also valid in twin pregnancies.     

Placental characteristics in twin transfusion syndrome

Summary The authors describe the histological features of the placenta in a typical case of twin-to-twin transfusion, with particular attention focused on the stereologic aspects. Villi from the anemic placental portion were slightly edematous, with small and inconspicuous vessels. The stereologic characteristics of this portion were nearer values of normal placentas. The plethoric region appears as a postmature organ, with a very thin trophoblast layer and numerous vasculo-syncytial membranes. The most dramatic alterations of this region were mainly related to the foetal capillary. According to the stereologic results, the consecutive circulatory alterations would facilitate the maternal-fetal exchanges in the plethoric placental territory, thus justifying the greater development of this twin.     

Placental injection studies in twin gestation

Vascular communication between placental vessels can occur when there is a fused placental mass in twin gestation. The presence of anastomotic channels can lead to the twin-twin transfusion syndrome in the fetuses. A study was conducted on 278 twin pairs to determine the incidence of vascular communication in fused twin placentas and the frequency of twin-twin transfusion syndrome. Anastomotic communication was found almost universally in monochorionic placentation and very rarely with dichorionic placentas. Twin-twin transfusion syndrome occurred uncommonly despite the high frequency of occurrence of cross-placental vascular communication. Misdiagnosis of intrauterine growth retardation in one twin can be avoided by determination of chorionicity by inspection of the placentas of twin gestation.     

Placental protein 10 (PP10) in normal pregnancy and cholestasis of pregnancy

The circulating concentrations of placental protein 10 (PP10) were measured by radioimmunoassay in 288 women with normal pregnancy and ten women (55 samples) with cholestasis of pregnancy. Serum PP10 levels were not affected by changes in incubation and storage temperature, and no diurnal variation was observed. The highest PP10 levels (36-85 micrograms/l) in normal pregnancy were found at 34 weeks. The postpartum decline of serum PP10 concentration corresponded to an average half-life of 18 h. In cholestasis of pregnancy at 32-39 weeks, the serum PP10 levels were found to be lower than normal. Negative correlation was observed between aminotransferase and PP10 levels in serum and between the bile acid levels and the PP10 concentration. These results suggest that the severity of maternal liver disorder is reflected in the circulating PP10 concentration.     

Placental pathology casebook. Complete hydatidiform mole with coexistent term twin pregnancy.

A case of twin pregnancy consisting of a complete hydatidiform mole with a coexistent, viable fetus is presented. The case is distinctive for its presentation on ultrasound, its unusually low levels of serum hCG, its remarkable histology, and its term delivery.     

Placental protein 10 (PP10) in normal pregnancy and cholestasis of pregnancy

Summary. The circulating concentrations of placental protein 10 (PP10) were measured by radioimmunoassay in 288 women with normal pregnancy and ten women (55 samples) with cholestasis of pregnancy. Serum PP10 levels were not affected by changes in incubation and storage temperature, and no diurnal variation was observed. The highest PP10 levels (36–85 μg/1) in normal pregnancy were found at 34 weeks. The postpartum decline of serum PP10 concentration corresponded to an average half-life of 18h. In cholestasis of pregnancy at 32–39 weeks, the serum PP10 levels were found to be lower than normal. Negative correlation was observed between aminotransferase and PP10 levels in serum and between the bile acid levels and the PP10 concentration. These results suggest that the severity of maternal liver disorder is reflected in the circulating PP10 concentration.     

Placental protein 14 (PP14) in late pregnancy

Placental protein 14 (PP14) was measured in 496 women in the last four weeks of pregnancy. There was no correlation between PP14 levels and the sex of the child, parity, age, or birthweight. A slight reduction in the median value was noted in pregnancies complicated by hypertension.     

Placental protein 5 and pregnancy zone protein in ovarian cysts and benign cystic ovarian tumors

Placental protein 5 (PP 5), a serine protease inhibitor, was measured by radioimmunoassay in benign ovarian cyst fluids, especially in follicular and luteal fluids. PP 5 was detectable in 12 out of 29 cystic fluids; the levels ranging from greater than 1.0 to less than 100 micrograms/l. PP 5 was not detectable in the corresponding serum samples. Protein of the "pregnancy zone" (PZ) was found in 3 out of 11 follicular fluids (9-38 mg/l). Local production of PP 5 and PZ in cystic epithelia of the ovary was taken into consideration.     

Placental protein measurements in complicated pregnancies. II. Pregnancy-related hypertension

Summary. Maternal serum levels of pregnancy-associated plasma protein A (PAPP-A), human placental lactogen (hPL) and schwangerschafts-protein 1 (SP1) were measured serially during the second and third trimesters in 753 women with a normal pregnancy when recruited during the second trimester. Thirty-seven pregnancies were complicated by pregnancy-related hypertension after 28 weeks gestation. Maternal levels of PAPP-A and SP1, and trends of levels in individual patients, could generally not be distinguished from those seen in patients with a normal pregnancy, and were unrelated to the time of onset of the disease, its severity or the occurrence of other complications with one exception, in which decreased levels of SP1 and hPL were seen. Mean levels of hPL were significantly lower ( P <0.05) at 35 weeks gestation. These data suggest that the measurement of the placental proteins examined here is of no value in the prediction of occurrence of pregnancy-related hypertension.     

Placental protein measurements in complicated pregnancies. III. Premature labour

Summary. Maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A), human placental lactogen (hPL) and schwangerschafts-protein 1 (SP1) were measured serially during second and third trimester in 753 women with a normal pregnancy when they were recruited to the study. In 24 women spontaneous premature labour occurred before 37 completed weeks and these women had significantly lower mean levels of serum SP1 at 29–31 weeks and at 33–34 weeks gestation but similar mean levels of serum PAPP-A and hPL at all gestations compared with corresponding values in normal pregnancy. The predictive value of an abnormal SP1 result was 5.2% at 29–31 weeks and 10.3% at 33–34 weeks. Furthermore, trends of levels of the three placental proteins in individual patients were similar to those seen in normal pregnancy, and the trends were unrelated to the occurrence of other complications and the time of onset of labour. This study suggests that measurements of the three placental proteins are unlikely to be of any value in the prediction of spontaneous premature labour.     

Placental protein measurements in complicated pregnancies. III. Premature labour

Maternal serum levels of pregnancy-associated plasma protein. A (PAPP-A), human placental lactogen (hPL) and schwangerschafts-protein 1 (SP1) were measured serially during second and third trimester in 753 women with normal pregnancy when they were recruited to the study. In 24 women spontaneous premature labour occurred before 37 completed weeks and these women had significantly lower mean levels of serum SP1 at 29-31 weeks and at 33-34 weeks gestations but similar mean levels of serum PAPP-A and hPL at all gestations compared with corresponding values in normal pregnancy. The predictive value of an abnormal SP1 result was 5.2% at 29-31 weeks and 10.3% at 33-34 weeks. Furthermore, trends of levels of the three placental proteins in individual patients were similar to those seen in normal pregnancy, and the trends were unrelated to the occurrence of other complications and the time of onset of labour. This study suggests that measurements of the three placental proteins are unlikely to be of any value in the prediction of spontaneous premature labour.     

Placental haemozoin and malaria in pregnancy

Malaria infections in pregnant women cause poor birth outcomes. Malaria pigment (haemozoin) accumulates in the placenta within macrophages and extracellularly, but its pathological significance is not understood. In order to study the potential role of haemozoin in malaria pathogenesis, we enrolled primigravid women at a Malawian government antenatal clinic and followed them through delivery. One hundred and thirteen women (71 per cent) out of 159 women followed through delivery were parasitaemic at least once. Mean placental haemozoin concentrations were significantly higher in women with delivery parasitaemias (223 ng/mg protein) than in women who never had a detectable parasitaemia (43 ng/mg protein; P<0.05), but were not significantly higher in women who were parasitaemic only during the antenatal period (67 ng/mg protein). Haemozoin was not associated with preterm delivery (PTD) or intrauterine growth retardation (IUGR) (P -values, 0.307-0.787). Thus, placental haemozoin is associated with malaria infection at the time of delivery and does not seem to be associated with poor birth outcome.     

Placental specific findings in twin pregnancies with hydramnion

Eleven of 157 twin pregnancies were complicated with polyhydramnios. Chorionicity, vascular anastomosis and insertion of the umbilical cord were analyzed with relation to polyhydramnios. 1. Polyhydramnios was found commonly in monochorionic placentation. 2. Vascular anastomosis was found in 40% of monochorionic polyhydramnotic placentas, which was lower than the anastomosis of monochorionic non-polyhydramniotic placentas. 3. The placentas with hydramnios had a higher incidence of abnormal umbilical insertion (marginal or velamentous insertion). These data indicate that incompetent vascular connections between the two fetoplacental circulations may be the pathogenesis of polyhydramnios.